Hearing test apparatus and method having automatic starting functionality

ABSTRACT

A hearing test device and method are disclosed which involve the placement of a testing probe in the ear canal of a test subject. The device analyzes responses to stimuli applied to the ear canal to determine whether the testing probe has been properly placed in the ear canal. The device may determine, for example, whether the probe is stable, whether it is sealed in the ear canal, whether the resulting volume of the ear canal is acceptable, and/or whether the stimuli delivery system is blocked in any way. If the device determines that the testing probe has been properly placed in the ear canal, the device automatically starts a hearing test without requiring any operator input.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 09/517,042 titled “HEARING TEST APPARATUS AND METHOD HAVINGAUTOMATIC STARTING FUNCTIONALITY” filed Mar. 2, 2000 now U.S. Pat. No.7,050,592, the complete subject matter of which is hereby incorporatedherein by reference, in its entirety.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

MICROFICHE/COPYRIGHT REFERENCE

Not Applicable

BACKGROUND OF THE INVENTION

Hearing test devices that monitor the condition within a human ear areknown. Such test devices generally require that the person performingthe test (the “operator”) place a test probe of the device within theear canal of a test subject. Once the probe is placed properly withinthe ear canal, the operator activates the device, usually by pressing abutton or the like. The device then emits test signals into thesubject's ear through the probe in the ear canal. In response to thetest signals emitted, the device receives response signals from the ear,likewise through the probe in the ear canal. Such response signalsreceived are then used to determine whether the ear is functioningproperly.

One such test device analyzes the distortion product otoacousticemissions (DPOAE) generated by the ear to determine middle ear function.More specifically, a DPOAE test device generates and emits two audibletones (i.e., test signals) at different frequencies into the ear canalof a subject. A healthy ear will produce, in response to the two audibletones, a response signal having a frequency that is a combination of thefrequencies of the two audible tones. Thus if the two audible tonesgenerated have frequencies of f1 and f2, respectively, a healthysubject's ear will emit a response signal having a frequency that is acombination of f1 and f2. The strongest response signal occurs at afrequency of (2)(f1)-f2, and is referred to as the distortion product.

In addition, DPOAE test devices also generally modify the frequencies ofthe audible tones transmitted into the ear canal over time during thecourse of the test. In response, a healthy subject's ear will emit adistortion product having a frequency that similarly changes over timeduring the course of the test. Generally speaking, the lack ofdistortion product otoacoustic emissions from the ear during the courseof the test is an indication of possible hearing loss.

Existing DPOAE test devices all use a probe that is inserted into theear canal of the test subject. Such a probe is either attached to thedevice via a cable, or is mounted on the device to form an integratedhand-held device. In either case, proper placement of the probe into theear canal is critical to obtaining accurate and useful DPOAEmeasurements. This is primarily due to the fact that otoacousticemissions produced by a healthy ear are extremely small in magnitude,typically in the range from −10 dB SPL to +20 dB SPL. Improper placementof the test probe in the ear canal may result in the inadvertent maskingof the emissions (and thus the triggering of a false negative response),in an inaccurate measurement, or in an otherwise invalid result. Properplacement of the test probe in the ear canal is generally determined byone or more of several factors. An operator may be required to insertthe probe deeply into the ear canal and/or to create a seal between theprobe and the ear canal. An operator may also be required to ensure thatthe probe is not blocked by a collapsed ear canal, by the canal wallitself, or by earwax. In addition, the operator may also be required todetermine that, once the probe is inserted, the resulting volume of theear canal is within a certain desirable range.

Consequently, it is often very difficult for an operator to know whetherproper placement of the probe has been achieved before the operatorinitiates the testing process. Moreover, particularly in the case of anintegrated hand-held device, the act of initiating the test (e.g.,pressing a start button) may shift the placement of the probe in the earcanal, which in and of itself may cause an inaccurate measurement. As aresult, an operator may be required to perform several tests in order toobtain accurate measurements, greatly slowing down the testing process.

In addition, in some cases, these problems may prevent an accuratemeasurement altogether. Specifically, a large proportion of DPOAEtesting is performed on infants. Typically, the infant is asleep whenthe testing is performed so that movement (and thus noise) is minimal.The process of properly placing and positioning the probe into aninfant's very small ear canal for the amount of time and number ofiterations needed to obtain accurate results often wakes the infant,which often makes the test impossible to complete, particularly if theinfant is crying.

Therefore, it is an object of the present invention to provide a testoperator with an indication that the testing probe is properly placedwithin the test subject's ear canal.

It is also an object of the present invention to provide automaticinitiation or starting of the test once the probe has been properlyplaced within the test subject's ear canal.

BRIEF SUMMARY OF THE INVENTION

A system, device and/or method that determines existence of at least onepre-test condition prior to testing hearing of a test subject,substantially as shown in and/or described in connection with at leastone of the figures, as set forth more completely in the claims.

These and other advantages and novel features of the present invention,as well as details of an illustrated embodiment thereof, will be morefully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates an integrated, hand-held hearing test or screenerdevice built in accordance with the present invention.

FIG. 2 is a block diagram of a hearing test or screener device built inaccordance with the present invention.

FIG. 3 is a flow chart illustrating generically the auto-start featureof the present invention.

FIG. 4 is a flow chart illustrating the auto-start feature of thepresent invention, in which tests are performed to analyze fourpre-start conditions, namely, temporal stability, low frequencyroll-off, noise limit, and channel balance.

FIG. 5 depicts screens that illustrate, via bar graph, volume and noiselevels measured by the device.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an integrated, hand-held hearing test or screenerdevice built in accordance with the present invention. The device 1includes a housing or terminal portion 3, an isolation body or assembly5 and a testing probe 7. The testing probe 7 includes an ear tip 9,which may be made of an elastic material, such as, for example, rubber.The testing probe 7 is integrated with the terminal portion 3 via theisolation body 5, which elastically couples or suspends the testingprobe from the terminal portion 3. Additional detail regarding theisolation body 5 can be found in co-pending U.S. patent application Ser.No. 09/285,938 filed Apr. 2, 1999, now U.S. Pat. No. 6,299,584, issuedOct. 9, 2001, which is hereby incorporated herein by reference, in itsentirety. While the testing probe 7 is illustrated in FIG. 1 as beingintegrated with the terminal portion 3, the testing probe 7 may beseparate from the terminal portion 3 and connected to the terminalportion 3 via a cable (not shown). In addition, the device 1 itself mayalso be a stationary (i.e., not hand-held) device having a probeconnected thereto via a cable, as is known in the art.

Referring again to FIG. 1, the terminal portion 3 includes a handleportion 11, a keyboard 13 and a display 15, which may be, for example,an LCD display. An operator grasps the handle portion 11, andmanipulates the keyboard 13 with the operator's thumb (or forefinger).The operator may view the display 15 before, during and after the test.The terminal portion 3 also includes a data port (not shown) located onan underside of the handle portion 11. The data port enables the device1 to be communicatively coupled to an external device, such as, forexample, a personal computer, for download of test and related data orupload of programming or other information. The terminal portion 3 mayalso include additional visual indicators 19 (besides the display 15),such as, for example, light emitting diodes (LEDS), for indicating tothe operator, for example, test status or the like. In FIG. 1, visualindicators 19 illustrate a “ready” status, a “test” status, and an“error” condition.

To perform a test, an operator grasps the handle portion 11 of theterminal portion 3 and moves the device 1 towards a test subject's ear(not shown). The operator then places the testing probe 7 into thesubject's ear such that the ear tip 9 is seated within the subject's earcanal.

As explained more completely below, a pre-test condition analysis isinitiated that determines whether certain condition(s) are satisfied,indicating that the testing probe is properly placed in the ear. Suchanalysis may be initiated automatically when the device is activated,or, automatically or by the operator when the testing probe 7 is placedin the subject's ear. In any case, if all condition(s) are satisfied,the actual ear test is automatically started by the device 1, withoutrequiring operator input.

FIG. 2 is a block diagram of a hearing test or screener device built inaccordance with the present invention. The block diagram of FIG. 2 isone embodiment of the device 1 of FIG. 1, which may be used, forexample, to perform DPOAE testing, as discussed above. Of course, otherembodiments exist that may not incorporate all of the components shownin FIG. 2, or that may incorporate components that are different than,or components in addition to, those shown in FIG. 2.

The embodiment of FIG. 2 will now be discussed with reference to DPOAEtesting. A digital signal processor (DSP) 21 generates digital signalsrepresentative of two audio tones of different frequencies and transmitsthe digital signals to a CODEC block 23 (i.e., an analog to digital anddigital to analog converter), which converts the digital signals toelectrical signals. The electrical signals are transmitted to an audiosource 25, which may be, for example, located in the testing probe 7 ofFIG. 1. The audio source 25 may comprise, for example, two audiospeakers. The two audio speakers respectively transduce electricalsignals into audible tones that are transmitted into the ear canal of atest subject. A microphone 27, which may, for example, be located in thetesting probe 7 of FIG. 1, receives responsive audio signals from theear of the test subject, and transduces the received audio signals intoelectrical signals representative of the received audio signals. Theelectrical signals are amplified by a microphone preamplifier 29,converted into digital signals by the block 23, and then communicated tothe DSP 21. The DSP 21 then uses the signals to perform DPOAE analysisas is known in the art.

The DSP 21 also communicates output signals to the LCD Display Driver 31which causes display of output data on the liquid crystal display 33and/or indication of test status on visual indicators (e.g., LEDs) 35.In general, the output data comprises, for example, test results or thelike. Output data, as such, may be displayed before, during and afterthe test. In fact, as discussed more completely below, the display maybe used by an operator before the test to assist in properly placing thetesting probe into the ear canal.

An operator may also use a headphone to further assist with properplacement of the testing probe in the ear. In one embodiment, the DSP 21communicates digital signals (e.g., representative of the audio signalsreceived from the ear) to a D/A converter 37, which converts the digitalsignals into electrical signals. The electrical signals are thenamplified by the amplifier 39 and communicated to a headphone output 41.The headphone output 41, which may be, for example, headphone jack 17shown in FIG. 1, is connected to a headphone assembly (not shown), whichtransduces the electrical signals into audio signals. Alternatively, theheadphone output may be located adjacent the data port on the undersideto the handle portion 11. With such a configuration, an operator may,for example, monitor the audio signals received from the ear to assistin the positioning and repositioning of the probe within the ear canal.Additional detail regarding audibly monitoring the condition in the earcan be found in co-pending U.S. patent application Ser. No. 08/971,520filed Nov. 17, 1997, now U.S. Pat. No. 6,056,698 issued May 2, 2000,which application is hereby incorporated herein by reference, in itsentirety.

In a further embodiment, discussed more completely below, the DSP 21communicates status signals, to the headphone output 41, which signalscan be audibly monitored by an operator via the headphones, to assistwith the positioning of the probe within the ear canal.

The DSP 21 also downloads or uploads data via the data port bycommunication with the RS-232 driver 43. In addition, keypad 44 enablesan operator to enter data and/or commands into the device 1.

As mentioned above, the actual testing phase performed by the testingdevice is automatically started after the testing probe has been placedin the ear canal and upon the completion of a pre-test conditionanalysis. In other words, the device does not begin the actual testuntil it determines that the testing probe has been properly placed inthe ear canal.

Such auto-start functionality simplifies the testing procedure. Sincethe actual hearing test begins once it is determined that the probe isproperly placed in the ear canal and without requiring further action bythe operator, there is a greater chance that accurate data will begenerated by the first hearing test attempt. As mentioned above, this isparticularly important for infants, who are most often tested while theyare sleeping. In addition, such auto-start functionality eliminates thepotential movement problems associated with the operator pressing abutton to initiate a test while the probe is in the subject's ear. Thisis particularly true for a hand-held device such as that shown in FIG.1, since the action of depressing a key often results in inadvertentprobe movement.

FIG. 3 is a flow chart illustrating generically the auto-start featureof the present invention. The functionality of FIG. 3 may be implementedusing a digital signal processor. As mentioned above, the auto-startfeature of the present invention involves a pre-hearing test conditionanalysis. The analysis begins by application of a series of stimuli tothe subject's ear (block 45) by a source, such as, for example, aspeaker. A receiver, such as, for example, a microphone receivesresponsive signals from the ear, which are measured both over time andfrequency. The measured signals are then used to perform one or moretests (blocks 47, 49, 51) to determine whether certain condition(s)exist (or do not exist, as the case may be) that indicate properplacement of the probe within the ear canal. If any one of the tests arefailed (or if the single test is failed if only one test is beingperformed), the process begins over again by application of the stimuliat block 45. If, however, all of the tests are passed (or if the singletest is passed if only one test is being performed), indicating that theproper condition(s) are present, the actual hearing test (e.g., a DPOAEtest) is automatically initiated (block 53).

FIG. 4 is a flow chart illustrating the auto-start feature of thepresent invention, in which tests are performed to analyze fourpre-start conditions, namely, temporal stability, low frequencyroll-off, noise limit, and channel balance. The functionality of FIG. 4may be implemented by the hearing test or screener device of FIGS. 1 and2.

The analysis begins by the application of stimuli to the ear canal(block 55) via the source or speakers 25 of FIG. 2. As discussed above,the stimuli is generated by the DSP 21 of FIG. 2. Such stimuli may, forexample, be alternating 300 Hz and 1 KHz audio tones. Such stimuli mayalso be non-audio stimuli. The microphone 27 receives responsive signalsfrom the ear which are measured over time by the DSP 21 and used toperform condition tests.

The first test performed is determining the temporal stability condition(block 57). The general purpose of this test is to estimate when theposition of the probe is stationary in the ear canal. Probe movementchanges the geometry of the enclosed space in the ear behind the end ofthe probe tip, and thus changes the magnitude of the response receivedfrom the ear. When the magnitude of such response is consistent overtime, temporal stability is assumed (i.e., the temporal stabilitycondition is satisfied).

Referring to block 57 of FIG. 4, if it is determined that the probe isunstable, the temporal stability condition test begins over again atblock 55. If, however, it is determined that the probe is stable, thenext test is initiated. Additional detail regarding determining thetemporal stability condition is set forth below.

The next test performed is determining the low frequency roll-offcondition, i.e., whether the response received from the ear exhibits anylow frequency roll-off (block 59). The low frequency roll-off conditionmay also be referred to as the spectral response condition. The generalpurpose of this test is to determine when the probe has formed a properseal in the ear canal. When a probe is not completely sealed to the earcanal, the low frequencies (usually <500 Hz) show a pronounced decreasein magnitude. The lowest frequencies show the greatest decrease inmagnitude, gradually decreasing as frequency increases. This conditionis known as low-frequency roll-off. When the shape of the low frequencycomponent of the response is determined to be within an acceptablerange, the condition is satisfied. In making such a determination, boththe slope of the low frequency component of the response and the rangeof values received may be considered.

Referring to block 59 of FIG. 4, if it is determined that the responseexhibits low frequency roll-off, the process begins over again at block55. If, however, it is determined that low-frequency roll-off issufficiently absent from the response, the next test is initiated.Additional detail regarding determining the spectral response conditionis set forth below.

The next test performed is determining whether any background noise isreceived along with the response from the ear (block 61). The generalpurpose of this test is to delay the starting of the hearing test ifthere is significant background noise present. A noise floor of theresponse may be determined from a frequency band where there is nostimuli energy. In one embodiment, the noise floor is calculated at thelowest frequency to be tested. When the noise floor is below anacceptable level, the test is passed. In general, if the noise level istoo high, for example, if there is background noise in the test room orif the test subject is swallowing or coughing, the actual hearing testis delayed. Otherwise, the unwanted noise may mask the signals needed toperform the actual hearing test.

Referring to block 61 of FIG. 4, if it is determined that the noisefloor is above the limit, the process begins over again at block 55. If,however, it is determined that the noise floor is below the limit, thenext test is initiated.

The next test performed is determining the channel balance condition,i.e., whether any blockages exist in the sound delivery system (block63). A set of stimuli is applied in an alternating fashion by the soundsource (e.g., two speakers), and the response received from the earcanal is measured. If one of the responses is not received, then it isassumed that a blockage exists. In general, this test is passed when theresponses received as a result of each speaker are within an acceptablerange.

Referring to block 63 of FIG. 4, if the responses are not within anacceptable range, it is assumed that the channels are unbalanced and theprocess begins over again at block 55. If, however, the responses arewithin an acceptable range, it is assumed that the channels are balancedand the actual hearing test is started (block 65).

Thus, as can be seen in FIG. 4, the actual hearing test automaticallystarts if and only if all of the pre-hearing test or pre-startconditions are satisfied. A system such as in FIG. 4 may, however,incorporate an override feature that enables the actual hearing test tobe started without performance of one or more of the condition tests.Such an override feature may be used in situations where a testsubject's physiology prevents passage of one or more of the conditiontests.. For example, if a test subject has a pressure equalization tubein the subject's tympanic membrane, the apparent ear canal volume wouldbe abnormally large, preventing the actual hearing test from starting(e.g., the spectral response condition test would be failed). In oneembodiment, the override feature is implemented so that a particularcondition test (or tests) is disabled and thus skipped. In anotherembodiment, all condition tests are disabled, in which case the actualhearing test is manually initiated by the operator.

In addition, as can be seen from FIGS. 3 and 4, the overall testingprocess involves two phases, the auto-start phase, during which thecondition tests are performed, and the hearing test phase, during whichan actual hearing test (such as a DPOAE test discussed above) isperformed. To assist an operator in positioning the probe in the earcanal during the auto-start phase, feedback may be provided to theoperator. Such feedback informs the operator of the status of theauto-start phase, and may take the form of visual queues, auditoryqueues, or both. Examples of visual queues include light indicators(such as visual indicators 19 of FIG. 1), text messages provided on adisplay (such as display 15 of FIG. 1), and graphical outputs providedon such a display. Examples of auditory queues include audible tones,generated speech queues, and the actual response measured by themicrophone (such as the microphone 27 of FIG. 2). Such auditory queuesmay be presented to the operator via external headphones, as discussedabove with respect to FIG. 2, and may comprise distinctive sounds foreach condition test performed during the auto-start phase.

While FIG. 4 shows four condition tests being performed, it should beunderstood that any number of those tests can be implemented in anygiven system. For example, following this description and prior to theclaims is 6 pages of an exemplary computer code listing (hereinafterreferred to as “the Code”) in which only the condition tests of blocks57, 59 and 63 of FIG. 4, namely, the temporal stability condition test,spectral response condition test, and receiver balance condition test,are performed. The Code is one embodiment of the auto-start phase thatmay be used by the device of FIGS. 1 and 2, and is being submitted aspart of the specification pursuant to 37 C.F.R. §1.96(b)(2).

The auto-start phase as set forth in the Code may be described asfollows. The stimuli applied to the ear canal consists of two pure tonesat different frequencies (F1, F2), with one tone applied per speaker.The tones F1 and F2 may be 300 Hz and 1000 Hz, for example. The responseis measured over a fixed interval of time. The frequency of the tonesare then reversed on the speakers and the response is measured again.This complete sequence is completed at least once, resulting in eachspeaker sending out four tones. Specifically, this complete sequence maybe illustrated as follows:

Stimuli # Speaker A Speaker B n − 3 F1 F2 n − 2 F2 F1 n − 1 F1 F2 n F2F1where n is the most recent stimuli. The stimuli may be applied everyone-third of a second, for example, resulting in a complete sequencetime of 1.2 seconds.

The complete sequence, therefore, starts with the initiation of thefirst stimuli (n-3), where Speaker A transmits a tone at F1 (e.g., 300Hz) and speaker B transmits a tone at F2 (e.g., 1000 Hz). One third of asecond later, the second stimuli (n-2) is initiated, where speaker Atransmits a tone at F2 (1000 Hz) and speaker B transmits a tone at F1(300 Hz). One third of a second later, the third stimuli (n-1) isinitiated, where speaker A again transmits a tone at F1 and speaker Btransmits a tone at F2. Finally, after another one third of a second,the fourth stimuli (n) is initiated, where again speaker A transmits atone at F2 and speaker B transmits a tone at F1.

Next, the responses to each tone transmitted are measured, where Pi(n)is the measured pressure (in dB) at frequency F1 for each stimuli n. Thepressure values (i.e., responses) are then used to perform the conditionanalysis.

More particularly, with regard to the temporal stability condition, theresponses from each speaker are compared over time at each frequencyaccording to the following equations:Speaker A |P1(n-1)−P1(n-3)|<=fit_bal2  (F1)|P2(n)−P2(n-2)|<=fit_bal2  (F2)Speaker B |P1(n)−P1(n-2)|<=fit_bal2  (F1)|P2(n-1)−P2(n-3)|<=fit_bal2  (F2)where fit_bal2 is the temporal balance parameter (in dB). The value ofthe temporal balance parameter, which may be, for example 2 dB,establishes how closely the response at each frequency must match inorder to conclude that the probe is stable.

Specifically, for speaker A, the difference between the responses forthe first tone (F1) (i.e., the difference in pressure resulting from thefirst and third stimuli) is calculated. Also, the difference between theresponses for the second tone (F2) (i.e., the difference in pressureresulting from the second and fourth stimuli) is calculated. The sametwo calculations are also performed for speaker B. If all fourcalculated values are no greater than 2 dB, for example, then thetemporal stability test is passed, and the conditional analysis proceedsto the spectral response condition test.

The spectral response condition test determines the difference in theresponse as a function of frequency, according the following equations:|P2(n)−P1(n-1)|<=fit_bal3 Speaker A|P1(n)−P2(n-1)|<=fit_bal3 Speaker Bwhere fit_bal3 is the spectral response parameter (in dB). In otherwords, the response generated by each speaker is compared at differentfrequencies (e.g., 300 Hz v. 1000 Hz) to determine if a leak in theprobe seal exists. If the calculated difference between the responsegenerated by each speaker is no greater than say, for example, 25 dB,then it is assumed that no leak is present.

The spectral response condition test also determines the averagereceiver response to the first tone (F1) according to the followingequation:

$\begin{matrix}{{Speaker}\mspace{34mu} B} & {\mspace{59mu} A}\end{matrix}$ fit_min  £(P 1(n) + P 1(n − 1))/2 <  = fit_maxwhere fit_min is the minimum spectral response at F1 (in dB) and fit_maxis the maximum spectral response at F1 (in dB). This calculation isessentially a test of the volume of the ear canal. If the averageresponse is within an acceptable range (e.g., between 32 dB and 50.5dB), then the volume is of the size expected from an ear canal. If theaverage response is greater than the range, the volume is too small,indicating a blocked or partially blocked condition. If the averageresponse is below the range, the volume is too large, indicating thatthe probe is not in the ear canal (or not far enough in).

When the “leak” and “volume” portions of the spectral response conditiontest are passed, it is assumed that the probe is placed a properdistance in the ear canal and the probe is properly sealed to the canal.The condition analysis then proceeds to the channel balance conditiontest.

The channel balance condition test compares the response generated byeach speaker at the same frequency according to the following equation:

$\begin{matrix}{\begin{matrix}{Speakers} & B & {\mspace{50mu} A}\end{matrix}\mspace{104mu}{{{{P\; 1(n)} - {P\; 1\left( {n - 1} \right)}}}<={fit\_ bal1}}} & ({F1}) \\{\begin{matrix}{Speakers} & A & {\mspace{56mu} B}\end{matrix}\mspace{104mu}{{{{P\; 2(n)} - {P\; 2\left( {n - 1} \right)}}}\pounds\mspace{11mu}{fit\_ bal1}}} & ({F2})\end{matrix}$where fit_bal is the receiver balance parameter (in dB). In other words,the response generated by tone F1 is compared at each speaker, and theresponse generated by tone F2 is compared at each speaker. If bothcomparisons result in a value of no greater than 4 dB, for example, thenit is assumed that both speakers are functioning (e.g., neither isblocked). Once this test is passed, the actual hearing test isautomatically started.

Again, in the present embodiment, all condition tests must be passed forthe actual hearing test to be automatically started. If any fail, theprocess begins over again by the transmission of two more sets of tonesare transmitted (corresponding to fifth and sixth stimuli). Theresponses are then reevaluated. Specifically, fifth and sixth sets ofresponses are generated, and they are used with the third and fourthsets of responses in performing the condition tests over again. Thefirst and second sets of responses are discarded. If one of thecondition tests is again failed, two more sets of tones are transmitted(corresponding to seventh and eighth stimuli), and seventh and eighthsets of responses are generated. They are used with the fifth and sixthsets of responses in performing the condition tests over again. Thethird and fourth sets responses are discarded. This process is repeateduntil all condition tests are passed.

As mentioned above, it may be desirable to provide the operator feedbackduring the auto-start phase of the testing process. The Code providesfor display of data to assist the operator in positioning the probe inthe ear canal. FIG. 5 depicts screens that illustrate, via bar graph,volume and noise levels measured by the device. Screen 71 shows acondition where the noise and volume are high, indicating that the probehas not yet been placed in the ear canal. Screen 73 shows a conditionwhere the noise and volume are lower, indicating to the operator that,while the probe is being positioned in the ear canal, it has not beeninserted properly (e.g., the probe is not deep enough and not sealed tothe ear canal). Screen 75 shows a condition where the noise and volumeare relatively low, indicating to the operator that the positioning islikely proper, and that the actual hearing test may be started soon. Ofcourse, other types of outputs on the display are also possible, asmentioned above, to assist the operator.

These and other objects of the invention are achieved in a hearing testdevice that transmits pre-hearing test condition analysis stimuli intothe ear canal of a test subject. The device analyzes signals receivedfrom the ear canal in response to the stimuli, and determines from thestimuli a condition or conditions related to the position of the testingprobe in the ear canal. If the condition or conditions are satisfied,the device automatically begins a hearing test. Satisfaction of thecondition or conditions as such generally indicates that the testingprobe is placed properly in the ear canal.

In one embodiment, the condition comprises a temporal stabilitycondition, which is a measure of the stability of the testing probe inthe ear canal. If it is determined that the testing probe is stable(i.e., stationary for a period of time) in the ear canal, the temporalstability condition is satisfied.

In another embodiment, the condition comprises a spectral responsecondition, which is a measure of the seal of the testing probe and ofthe volume of the ear canal. If it is determined that the testing probeis sealed in the ear canal and the volume of the ear canal is within anacceptable range, the spectral response condition is satisfied.

In yet another embodiment, the condition comprises a channel balancecondition, which is a determination of whether any blockages exist inthe sound delivery system. If a response is not received to one of thestimuli, then a blockage is assumed. If the responses received arewithin an acceptable range, then the condition is satisfied.

The hearing test device also includes a display that provides anindication of the volume behind the testing probe, as well as the noisebeing received by the device, to assist the operator in properlypositioning the testing probe in the test subject's ear canal.

Many modifications and variations of the present invention are possiblein light of the above teachings. Thus, it is to be understood that,within the scope of the appended claims, the invention may be practicedotherwise than as described hereinabove.

1. A hearing test device comprising: signal generation circuitry forgenerating audio frequency signals for transmission, via a test probe,into an ear canal of a test subject; receiver circuitry for processingresponse signals received from the ear canal of the test subject; atleast one processor for determining, using at least the responsesignals, that at least one pre-test condition of the test probe issatisfied; and user feedback circuitry, communicatively coupled to theat least one processor, to aid a user in proper probe placement.
 2. Thehearing test device of claim 1, wherein the audio frequency signalscomprise one or more pure tones.
 3. The hearing test device of claim 1,wherein the at least one pre-test condition is satisfied upon detectionof temporal stability of the test probe.
 4. The hearing test device ofclaim 3, wherein temporal stability is indicated when response signalshave an essentially consistent magnitude over a period of time.
 5. Thehearing test device of claim 1, wherein the at least one pre-testcondition is satisfied upon detection of proper placement of the testprobe in relation to the ear canal.
 6. The hearing device of claim 5,wherein proper placement is indicated when low frequency roll-off of theresponse signals is within a predetermined range.
 7. The hearing testdevice of claim 1, wherein the at least one pre-test condition issatisfied upon detection of an acceptable level of noise in the responsesignals.
 8. The hearing text device of claim 7, wherein an acceptablelevel is less than a predetermined noise level.
 9. The hearing testdevice of claim 1, wherein the at least one pre-test condition issatisfied upon detection of proper functioning of the test probe intransmitting audio frequency signals and receiving response signals. 10.The hearing device of claim 9, wherein proper functioning is indicatedwhen the amplitude of the response signals in the presence of generatedaudio frequency signals is above a predetermined level.
 11. The hearingtest device of claim 1, wherein the user feedback circuitry comprises avisual display.
 12. The hearing test device of claim 11, wherein thevisual display comprises a light emitting diode display.
 13. The hearingtest device of claim 1, wherein the feedback circuitry is locatedproximate the test probe.
 14. The hearing test device of claim 1,wherein the user feedback circuitry comprises an audible signal.
 15. Thehearing test device of claim 1, wherein the determining automaticallyproceeds upon placement of the test probe in an ear of the test subject.16. The hearing test device of claim 1, wherein the hearing test devicefurther comprises: data port circuitry for communication with a deviceexternal to the hearing test device.
 17. The hearing test device ofclaim 1, wherein the processor automatically performs a hearing test onthe test subject upon determining satisfaction of the at least onepre-test condition.
 18. The hearing test device of claim 16, wherein thehearing test comprises a distortion product otoacoustic emissions(DPOAE) test.
 19. The hearing test device of claim 1, wherein the testprobe, during use, is positioned within the ear canal.
 20. A method ofoperating a hearing test device, the method comprising: receivinginformation identifying, from a plurality of pre-test conditions fordetermining whether a testing probe is properly positioned in an earcanal, pre-test conditions to be satisfied before initiation of ahearing test; performing pre-testing to determine whether all identifiedpre-test conditions are satisfied; automatically initiating the hearingtest, if all identified pre-test conditions are satisfied; andcontinuing performing pre-testing, if all identified pre-test conditionsare not satisfied.
 21. The method of claim 20, wherein the informationidentifying pre test conditions is received from a device external tothe hearing test device.
 22. The method of claim 20, wherein theinformation identifying pre test conditions is received via user inputat the hearing test device.
 23. The method of claim 20, wherein theplurality of pre-test conditions comprises one or more of a temporalstability condition, a spectral response condition, a channel balancecondition, and a noise level condition.
 24. The method of claim 23,wherein the temporal stability condition is satisfied when responsesignals received from an ear canal of a test subject in response to anaudio signal transmitted into the ear canal are consistent in magnitudeover a period of time.
 25. The method of claim 23, wherein the spectralresponse condition is satisfied when the difference in magnitude ofresponse signals received from an ear canal of a test subject inresponse to audio signals of different frequencies transmitted into theear canal is less than a predetermined value.
 26. The method of claim23, wherein the channel balance condition is satisfied when each of tworesponse signals received from an ear canal of a test subject inresponse to each of two audio signals transmitted into the ear canalusing separate audio transducers differs by no more than a predeterminedamount.
 27. The method of claim 23, wherein the noise level condition issatisfied when a noise level of a response signal received from an earcanal of a test subject is no greater than a predetermined value. 28.The method of claim 20, further comprising: downloading hearing testdata to a device external to the hearing test device.
 29. The method ofclaim 20, further comprising: notifying a user when all identifiedpre-test conditions are satisfied.
 30. The method of claim 29, whereinthe notifying comprises a visual indication.
 31. The method of claim 20,wherein the hearing test comprises a distortion product otoacousticemissions (DPOAE) test.